A tremendous variety of token-actuated devices are known and have proved commercially successful, including (but not limited to) parking meters which control individual parking spaces, vending machines, newspaper racks, electronic games, and jukeboxes. Many token-actuated devices respond to the insertion of a token which is legal tender (that is, a coin). Other token-actuated devices respond to a token which is not itself legal tender and which is ordinarily specifically designed for use in a particular type of token-actuated device. (As used herein the term "token" includes both a token which is legal tender in some nation--that is, a coin--and a specially-designed token which is not legal tender.)
Many early token-actuated devices were wholly mechanical. Examples of such devices are early parking meters, such as those disclosed in U.S. Pat. No. 1,799,056 to Miller and U.S. Pat. No. 2,603,288 to Sollenberger.
Although mechanical token-actuated devices remain useful, mechanical devices have disadvantages in comparison with electronic devices. Mechanical devices generally have many more moving parts than electronic devices; those moving parts tend to need repair or replacement more frequently than electronic parts. Replacing mechanical parts ordinarily requires much more labor than replacing electronic parts.
Electronic devices have other advantages in comparison with mechanical devices. For example, electronic devices can economically provide a wide variety of special functions which would be prohibitively expensive to implement in a wholly mechanical device.
Thus, those working in the field of token-actuated devices have sought to develop token-actuated devices which incorporate electronic components. See, for example, U.S. Pat. No. 3,757,916 to Selby; U.S. Pat. No. 4,031,991 to Malott; U.S. Pat. No. 4,792,032 to Shapiro; U.S. Pat. No. 4,848,556 to Shah, Pester, and Stern; and U.S. Pat. No. 4,823,928 to Speas.
One problem which has impeded the use of electronic components in token-actuated devices is inadequate repeatability in the operation of electronic token validation systems. Many token-actuated devices incorporate token validation systems to indicate whether an inserted token is valid or invalid. For example, parking meters should distinguish between a valid coin (such as a United States quarter in parking meters located in the United States) and an invalid coin (such as a Canadian quarter for parking meters located in the United States) or an invalid token (such as a worthless slug). Mechanical parking meters incorporate a variety of mechanical token validation systems for performing such tests. Those mechanical token validation systems have proved adequate in the sense that they yield the same result--that is, they accept or reject the same token--in a consistently repeatable and reproducible manner as long as their mechanical parts have not become worn. However, mechanical token validation systems are severely limited in the types of tests of token characteristics which they can perform.
Replacing the mechanical token validation systems with electronic token validation systems is desirable for the reasons noted above; in particular, electronic token validation systems can perform a much wider variety of tests of token characteristics than mechanical token validation systems. However, conventional electronic token validation systems produce results which are not sufficiently repeatable (the conventional electronic validation systems often do not yield the same acceptance or rejection result for the same token) and/or not sufficiently reproducible (the conventional electronic validation systems do not yield the same acceptance or rejection result for different tokens of the same type)--even though the electronic validation system is not worn and in fact is operating as satisfactorily as it is able to operate. Although those working in the art continue to devote considerable attention to improving the electronic token characteristic sensors which are used in electronic token validation systems, the problems of inadequate repeatability and inadequate reproducibility continue to impede progress toward wider use of electronic token-actuated devices.
Thus, there has been and is a need for improving the repeatability and the reproducibility of the token validation results which electronic token validation systems generate.
Another problem which has impeded the wider use of electronic token-actuated devices is the difficulty of designing electronic token validation systems to detect certain types of special-purpose tokens.
As noted above, many electronic token validation systems are designed to validate tokens which are not coins. Coins ordinarily are made of metal and have a metal content which is uniform with increasing radius from the axis of the coin disk. Some types of token actuated devices--for example, the turnstiles of some subway systems or the fareboxes of some mass transit systems--require a payment amount which is either greater than the value of a simple grouping of common coins or which is not convenient to provide for in coin acceptance devices. As an example, a subway fare may be 90 cents--an amount which could be reached by numerous combinations of numerous coins of the same or different denominations. For such fares it may be more efficient to accept a single, special-purpose token rather than various combinations of numerous coins of the same or different denominations.
Such special-purpose tokens are often made of metal disks which do not have a uniform metallic content with increasing radius from the axis of the token disk. One common token of this type--the present-day New York City subway token--has one type of metal in approximately the first one-third of the radius extending from the axis of the token disk and another type of metal in the remainder of the token disk. Electronic token validation systems designed to validate coins often do not work well in validating such special-purpose tokens. In particular, conventional token characteristic sensors (for example, frequency-shift sensors) use the change in inductance or change in capacitance of some type of circuit as a metal token passes through a token-actuated device to produce a signal indicative of the token characteristics. Such conventional sensors are difficult to use with a token such as a New York City subway token. If two such conventional token characteristic sensors are mounted close together to permit sensing the different metals in the disk of the New York City subway token, the magnetic and/or electric fields of each sensor may interfere with the other sensor. This makes accurate detection of the characteristics of an inserted token very difficult. Thus, there has been and is a need to improve the design of electronic token validation systems so that those systems can be used effectively to validate such special-purpose tokens.
Another problem which has impeded the wider use of electronic token-actuated devices is the amount of current which an electronic token-actuated device draws in its operation. Many types of token-actuated devices-- particularly parking meters and newspaper vending machines--are ordinarily used in places where the devices cannot be conveniently connected to electric power lines. Thus, those types of token-actuated devices must usually rely on batteries for electric power. (U.S. Pat. No. 4,823,928 to Speas also discloses the use of solar cells.) Because a battery can only supply a limited amount of current before the battery must be recharged and/or replaced, a battery-powered token-actuated device should draw as little current as possible.
The requirement for low current consumption has limited the ability of battery-powered token-actuated devices--such as parking meters--to perform certain desirable functions. Thus, there has been and is a need to develop improved designs so that electronic token-actuated devices can perform desired functions with low current consumption.
One desirable function in a token-actuated device is for the token-actuated device to return a token which the token-actuated device has not accepted as a valid token. A token-actuated device frequently rejects a token which is in fact a valid token but which has become worn or which for some other reason does not satisfy the acceptance criteria which the token-actuated device employs. Such tokens should be returned to the user rather than simply kept by the token-actuated device. Users become annoyed when a token-actuated device keeps but does not respond to a valid (even if worn, and especially if not worn) token inserted in the device. Even if the rejected token is in fact an invalid token (for example, a worthless slug inserted in a token-actuated device which responds to a quarter), holding the invalid token in a token receptacle wastes space which could be occupied by valid tokens and requires an eventual sorting step to separate the valid tokens from the invalid tokens.
Unfortunately, many conventional ways of returning tokens which are not accepted by the token-actuated device draw more power than is acceptable in a free-standing, battery-powered, token-actuated device such as a parking meter or a newspaper vending rack. Thus, there has been and is a need for a token return system which draws less current.